1. Field of the Invention
The present invention relates to a battery module having a plurality of unit batteries. In particular, the present invention relates to a battery module having improved structure of partitioning walls between its unit batteries to provide enhanced battery durability and efficiency.
2. Description of the Related Art
In general, a secondary battery, i.e., a unit battery, may be a type of a rechargeable battery, as opposed to a primary battery that cannot be recharged. A low capacity secondary battery may include a single battery cell to supply power to portable electronic device, such as mobile phones, laptop computers, and camcorders. A high capacity secondary battery may include a plurality of battery cells, i.e., battery module, to supply power to electrical motors, such as a motor of a hybrid vehicle.
A conventional battery module may include a plurality of unit cell batteries, wherein each unit battery may include an electrode group, a separator positioned between positive and negative electrodes in the electrode group, positive and negative terminals connected to charge collectors, and a casing with a cap to store the batteries and electrodes therein. The casing may usually be formed to have predetermined intervals between the unit batteries, such that partitioning walls may be interposed therein.
A conventional battery module may also include end plates at the outermost ends thereof. The end plates may be pressed towards each other with the unit batteries therebetween in order to reduce the thickness of the electrode groups of the unit batteries and, thereby, improve the efficiency, i.e., charging/discharging, of the battery units.
However, when the end plates are pressed to reduce the thickness of the electrode groups, the conventional structure of the partitioning walls may prevent sufficient compression. In particular, the conventional partitioning walls may be structured such that their edges may be in contact with the casing of the battery module, thereby minimizing the amount of inward compression the surface of the casing may undergo. Such minimized inward compression may result either in insufficient thickness reduction of the electrode group, i.e., reduced shifting distance of ions, or in excessive force, thereby subjecting the unit batteries to potential deformation and damage.
Therefore, there exists a need for a battery module having an improved partitioning wall structure providing enhanced battery durability and efficiency.